The present invention relates to a biaxially oriented polyester film having a uniform surface and being excellent in running property and wear resistance.
Polyester films, in particular, biaxially oriented polyester films are widely used as a material in the industrial fields. With the recent demand for higher-grade polyester films for various purposes, they are strongly required to have uniform surfaces. However, the conventional polyester films are insufficient in wear properties represented by the drop of abrasion dusts from film surface. The improvement of wear properties has been demanded.
Improvements of wear properties have conventionally been made mainly by controlling the orientation of the film as a matrix or adding various kinds of particles in a polyester film, but are still insufficient.
As a result of studies undertaken by the present inventor so as to solve the above-described problems, it has been found that a film containing specific inorganic particles is excellent in surface properties, running properties and wear resistance. The present invention has been achieved on the basis of this finding.